Electric Speed Limit/Radar signs

[Jaiguru]

Not sure what the correct name for them is but the title description is the best I could come up with. The speed limit signs with the led beneath posting your speed and flashes when you're over the speed limit.

Every single one I drive by reads my speed at about 5mph below what my spedometer is reading. Should I get my spedo checked or is this some evil ploy by the cops to get you to speed up and hand you a ticket 1/2 a mile down the road?

 

[mwmorph]

Originally posted by: Jaiguru
Not sure what the correct name for them is but the title description is the best I could come up with. The speed limit signs with the led beneath posting your speed and flashes when you're over the speed limit.

Every single one I drive by reads my speed at about 5mph below what my spedometer is reading. Should I get my spedo checked or is this some evil ploy by the cops to get you to speed up and hand you a ticket 1/2 a mile down the road?

Speedometers are not always accurate and if it is inaccurate, it is usually on the high side. On my car, doing 60 is a indicated 56 on GPS and on my bike, doing 85 is a indicated 77 on the GPS.

This isnt always true though, no my parent's van, doing 50 is exactly 50.

 

[FallenHero]

The angle at which the radar is hitting you makes a difference. If its hitting you at a 70 degree angle, its gonna show you are going slower than you actually are vs. one that is hitting you at a 1-5 degree angle. Its why cops will get you from a pretty decent distance and not terribly close. I wouldn't trust it...those things are used to make the public aware of their speed and perhaps have them slow down. Alot don't realize how fast they are going.

 

[FallenHero]

The angle at which the radar is hitting you makes a difference. If its hitting you at a 70 degree angle, its gonna show you are going slower than you actually are vs. one that is hitting you at a 1-5 degree angle. Its why cops will get you from a pretty decent distance and not terribly close. I wouldn't trust it...those things are used to make the public aware of their speed and perhaps have them slow down. Alot don't realize how fast they are going.

 

[Jaiguru]

Originally posted by: FallenHero
The angle at which the radar is hitting you makes a difference. If its hitting you at a 70 degree angle, its gonna show you are going slower than you actually are vs. one that is hitting you at a 1-5 degree angle. Its why cops will get you from a pretty decent distance and not terribly close. I wouldn't trust it...those things are used to make the public aware of their speed and perhaps have them slow down. Alot don't realize how fast they are going.

Seems logical enough to be true. Thanks!

 

[FeuerFrei]

Those things are great. If it weren't for them I wouldn't know my speedo reads 4 mph high.

 

[BoomerD]

In many places, those "Your Speed Is" trailers have not only a radar unit, but a camera, and can be used to issue speeding tickets...

Gotta be careful. MOST either aren't challenged in court, or are upheld in court...Like red-light cameras, they have to show your license plate and the face behind the wheel.

 

[Squisher]

They usually have one at the airport and it's spot on. I go there usually twice a week to drop off and pick up the wife.

 

[jlfirehawk]

The ones around here do not have a camera but almost all have a computer inside that record every detail that way the cops know when to put up speed traps.

 

[SoulAssassin]

Am I the only person who speeds up when you see them? I like to try to beat my high score.

 

[spidey07]

Of course they are accurate.

 

[JulesMaximus]

Originally posted by: Jaiguru
Not sure what the correct name for them is but the title description is the best I could come up with. The speed limit signs with the led beneath posting your speed and flashes when you're over the speed limit.

Every single one I drive by reads my speed at about 5mph below what my spedometer is reading. Should I get my spedo checked or is this some evil ploy by the cops to get you to speed up and hand you a ticket 1/2 a mile down the road?

Do you have aftermarket wheels on your car?

I've found those signs to be pretty accurate.

 

[JulesMaximus]

Originally posted by: SoulAssassin
Am I the only person who speeds up when you see them? I like to try to beat my high score.

I do when I'm on my bike. There is sometimes one on my commute home but it's at the top of a steep hill so the best I've been able to get is 12-13mph...which is exactly what my Garmin GPS cyclocomputer reads.

 

[PingSpike]

I like when its hitting two different cars and starts to wig out switching between the different speeds.

 

[Jaiguru]

Originally posted by: JulesMaximus

Originally posted by: Jaiguru
Not sure what the correct name for them is but the title description is the best I could come up with. The speed limit signs with the led beneath posting your speed and flashes when you're over the speed limit.

Every single one I drive by reads my speed at about 5mph below what my spedometer is reading. Should I get my spedo checked or is this some evil ploy by the cops to get you to speed up and hand you a ticket 1/2 a mile down the road?

Do you have aftermarket wheels on your car?

I've found those signs to be pretty accurate.

I don't.

 

[JulesMaximus]

Originally posted by: Jaiguru

Originally posted by: JulesMaximus

Originally posted by: Jaiguru
Not sure what the correct name for them is but the title description is the best I could come up with. The speed limit signs with the led beneath posting your speed and flashes when you're over the speed limit.

Every single one I drive by reads my speed at about 5mph below what my spedometer is reading. Should I get my spedo checked or is this some evil ploy by the cops to get you to speed up and hand you a ticket 1/2 a mile down the road?

Do you have aftermarket wheels on your car?

I've found those signs to be pretty accurate.

I don't.

What kind of car and how fast are you going when you get tagged by the sign?

 

[Jaiguru]

98 Acura Integra. Today, when passing one, my spedo was reading 56-57 mph but the sign was clocking me at 50. I was in the far right lane and no one else was on the road at the time.

 

[hanoverphist]

the ones ive come across have been pretty accurate. i have larger tire than originally came with the truck, and on long trips i recalc the miles throughout (to keep my self occupied) and found out that im running about 90%. as in every 10 miles i go, my odometer only registers 9 miles. calcing the speed at that, when i do 50 im actually doing 55. every one of those signs has been that same 10% deficit so far, including the radar trap that got me a speeding ticket. mebbe its just az that makes sure they are accurate, mebbe they all are... i dunno.

 

[mrrman]

usually I speed up to see how fast I am going lol

 

[JulesMaximus]

Originally posted by: Jaiguru
98 Acura Integra. Today, when passing one, my spedo was reading 56-57 mph but the sign was clocking me at 50. I was in the far right lane and no one else was on the road at the time.

That's a pretty large margin of error. I'd have it checked out. You sure the car is completely stock?